1. Field of the Invention
This invention relates generally to crawl space and basement venting, and in particular, to the flood venting of enclosed spaces within a foundation.
2. Description of Related Art
Building Officials and Code Administrators (BOCA) regulations mandate that buildings with subgrade level, enclosed spaces, such as crawl spaces, located in low-lying coastal flood areas, provide for adequate relief from tidal flood waters stemming from oncoming tides and receding waters. As a solution to the problem of tidal flood waters, local regulations and good construction practice employ the use of venting. However, while venting allows for tidal waters to ebb and flow through the enclosed space, the venting should not allow access by small animals, insects, and other pests through the openings in the enclosed space. In particular, BOCA regulations require flood venting for all new construction in low lying coastal flood areas. Furthermore, NOCA regulations require the use of flood venting where renovations to an existing structure exceed fifty percent of the value of the property.
Notwithstanding, good construction practice also embraces the use of vents which can be opened during warmer months to allow for air ventilation to permit moisture to escape from crawl spaces, while retaining the ability to close during colder months to prevent the circulation of cold air around exposed plumbing in crawl spaces. Thus, because the use of screening and louvers is necessary to achieve both the warm weather and cold weather requirements of proper venting, a flood vent must be able to automatically remove the louver and screen barrier when confronted with free flowing tidal flood water.
Generally, a wide variety of devices have been developed which may be utilized to provide pressure relief from both liquid and gaseous forces. With respect to gas pressure relief devices, U.S. Pat. No. 3,680,239, issued Aug. 1, 1972 to Burtis for PRESSURE EQUALIZING VALVE, discloses a device to relieve overpressure and underpressure in the opening and closing of a door of a refrigerated space. U.S. Pat. No. 2,774,116, issued Dec. 18, 1956 to Wolverton for DOUBLE ACTING RELIEF VALVE, U.S. Pat. No. 2,798,422, issued Jul. 9, 1957 to Bourque for AIR RELIEF MEANS FOR DOORS, and U.S. Pat. No. 3,123,867, issued Mar. 10, 1964 to Combs for VESTIBULE PRESSURE EQUALIZER relate to the equalization of differential air pressure experienced in the swinging of one door relative to another door. Additionally, U.S. Pat. No. 2,105,735, issued Jan. 18, 1938 to Hodge for PRESSURE RELEASING APPARATUS, and U.S. Pat. No. 4,116,211, issued Sept. 26, 1978 to Kamezaki for AIR PRESSURE CONTROL APPARATUS FOR A HOT OR COLD STORAGE CHAMBER, teach methods to release pressure in closed chambers resulting from changing temperatures within the chamber. In particular, the Kamezaki apparatus utilizes a swinging damper hinged at the top of an enclosing frame. Nevertheless, neither the Kamezaki apparatus nor other inventions contemplate the use of a vented damper able to relieve pressure resulting from fluid flow.
Correspondingly, several devices have been developed which provide relief from overpressure resulting from the flow of water and other liquids. U.S. Pat. No. 4,349,296, issued Sept. 14, 1982 to Langeman for IRRIGATION DITCH GATE describes a gate for an irrigation ditch, which during normal conditions through the use of tensioned springs, maintains flood gates in a closed position, but upon flood conditions, allows for the gates to open. U.S. Pat. No. 3,939,863, issued Feb. 24, 1976 to Robison for BASEMENT SUMP CONSTRUCTION discloses a basement drain containing a trap for the prevention of back flow of flood water. U.S. Pat. No. 4,174,913, issued Nov. 20, 1979 to Schliesser for ANIMAL GUARD FOR FIELD PIPE relates to an invention which, while allowing for the free-flow exit of debris carrying effluents from an open pipe end, prevents animal entry into the pipe. Still, none of the aforementioned devices contemplate the integration of a liquid flow control device with a temperature controlled ventilation system.
Presently, several patents disclose methods for ventilating enclosed foundation spaces. U.S. Pat. No. 5,293,920, issued Mar. 15, 1994 to Vagedeg for LOUVERED BASEMENT VENT, and U.S. Pat. No. 5,487,701, issued Jan. 30, 1996 to Schedegger et al. for PLASTIC FOUNDATION VENT, embody louvered basement vents which can be manually adjusted to limit air flow in colder temperatures, and to maximize air flow in hotter conditions. U.S. Pat. No. 5,460,572, issued Oct. 24, 1995 to Waltz et al. for FOUNDATION ventilator discloses merely a one-piece molded plastic foundation ventilator without louvers. The Waltz invention, however, contemplates the manual use of hinged doors to regulate air flow through to the foundation. U.S. Pat. No. 2,754,747, issued Jul. 17, 1956 to Bertling for AIR REGISTER OR LOUVER, embodies a hinged, louvered door, designed to facilitate the maintenance of the screen behind the louvered door. Nonetheless, the louvers are designed to be operated manually by the user.
All of the aforementioned foundation ventilators contain screening to prevent small animals, insects and other pests from gaining access to the enclosed area. Significantly, none of the aforementioned foundation ventilators will act as a water pressure relief valve in response to the ebb and flow of tidal waters. Furthermore, none provide for the automatic adjustment of louvers in response to increasing or decreasing temperature so as to prevent either the rotting of the elements of the structure's foundation, or the freezing of pipes within the enclosed space. Accordingly, the prior art has not provided an integrated method to automatically ventilate an enclosed space of a foundation while allowing for the relief of liquid pressure on either side of the vent, and preventing small animals, insects and pests from entering the enclosed space.